The invention relates to a system for determining characteristics of an object or a sample and a method for determining characteristics of an object or a sample.
Electromagnetic radiation is widely used for non-destructive testing of materials and objects. For example, terahertz radiation is used having a frequency of e.g. approximately 100 GHz to 10 THz. Many modern materials such as polymers, ceramics and compound materials are at least to some extent transparent for that kind of radiation such that for example defects (and the depth of defects) and/or layer thicknesses can be determined using such electromagnetic waves.
However, most terahertz systems use pulsed terahertz radiation, wherein using the transmission time of the pulses, the location of origin of the pulses can be determined such that spatially resolved measurements are possible. These measurements thus can be used e.g. for providing three-dimensional reconstructions of an object. The pulsed systems, however, only allow spatially limited, punctual measurements or require long acquisition times if larger objects shall be investigated.